1. Field of the Invention
This invention relates to a color printer, fax machine, photocopier, or other image formation device which forms images using electrophotographic technology, and in particular relates to an image formation device enabling switching between a color printing mode and a monochrome printing mode, and which moreover affords increased flexibility in mounting a developing unit in the monochrome printing mode.
2. Description of the Related Art
Image formation devices which form images using electrophotographic technology, provided for example in color printers, have an image carrier in which is formed an electrostatic latent image according to image data; a charging unit which charges the outer surface of the image carrier; an exposure unit which exposes the outer surface of the charged image carrier according to image data, to form an electrostatic latent image; a developer device which supplies toner, as a developing agent, to the electrostatic latent image to develop a toner image; and a transfer unit which causes the toner image to be transferred to a media. The developer device detachably holds a plurality of developing units which house color toners, and has a developer unit holder which causes the appropriate developer unit to be brought into proximity with the image carrier according to the development timing. This developer unit holder is normally a rotatably controlled developing rotary. When performing color printing, development units with color toner in a plurality of colors, for example, four colors (yellow or Y, magenta or M, cyan or C, and black or K) is mounted in the developing rotary. When performing monochrome printing, a black development unit is mounted in the developing rotary.
An image formation device has been proposed which can be put into a color printing mode in which a four-color development unit is mounted, or into a monochrome printing mode in which only a black development unit is mounted, with the user able to switch between the two modes as appropriate. Such an image formation device has been proposed in, for example, Japanese Patent Laid-open No. 2003-43773 (Publication Date: Feb. 14, 2003), Japanese Patent Laid-open No. 2003-316106 (Publication Date: Nov. 6, 2003), and Japanese Patent Application No. 2003-160059.
In Japanese Patent Laid-open No. 2003-43773 and Japanese Patent Application No. 2003-160059, an image formation device is disclosed in which the color printing mode is set when four color development units are mounted in the developing rotary, and the monochrome printing mode is set when a single black development unit is mounted only in the mounting position for the black development unit of the developing rotary, with no development units mounted in the other mounting positions, which are CMY positions.
In Japanese Patent Laid-open No. 2003-316106, an image formation device is disclosed in which the mounting positions in the developing rotary are not in fixed one-to-one correspondence with development units in four colors, and a development unit of an arbitrary color can be mounted in an arbitrary mounting position. In this image formation device, information on the color of the developing agent is read from memory provided in the development unit, to detect which color development units are mounted in which positions of the developing rotary, and based on the detected positions, rotation of the developing rotary is controlled in the development process. Specifically, in Japanese Patent Laid-open No. 2003-316106, when development units in the four CMYK colors are mounted, the device operates as a color printer, and when only the black development unit is mounted, the device operates as a black monochrome printer.
Further, an image formation device has been proposed in which, by mounting black development units in all four of the mounting positions of the developing rotary and setting the monochrome printing mode, the number of times development units need to be replaced can be reduced. Such an image formation device is disclosed in Japanese Patent Laid-open No. 2002-351190 (Publication Date: Dec. 4, 2002). In this image formation device, by mounting four black development units in the four mounting positions of the developing rotary for color printing, reading memory provided in the development units, detecting the mounting positions, color information, and amount of toner remaining, and by using the black development units in order, the frequency of replacement of development units in monochrome printing mode can be reduced, even for small-type development devices.
Japanese Patent Laid-open No. 2003-43773, Japanese Patent Laid-open No. 2003-316106, and Japanese Patent Application No. 2003-160059 all disclose image formation devices capable of switching between a color printing mode and a monochrome printing mode; but in all cases, a four color (CMYK) development units must be installed in order to switch to color printing mode, whereas in order to switch into monochrome printing mode, only a development unit of the same color (for example, black) need be installed. Consequently in order to switch from a color printing mode to a monochrome printing mode, of the four color (CMYK) development units, the three color (CMY) development units other than black must be removed. Conversely, in order to switch from the monochrome printing mode to the color printing mode, three color (CMY) development units must be installed in addition to the already-installed black development unit.
For example, the image formation devices of Japanese Patent Laid-open No. 2003-43773 and Japanese Patent Application No. 2003-160059 operate in color printing mode when four color (CMYK) development units are installed in fixed positions of the development rotary, and operate in monochrome printing mode when a black development unit is installed in the black position of the development rotary. Hence in order to switch from color printing mode into monochrome printing mode, the three color (CMY) development units other than black must all be removed. If any of the three color (CMY) development units is left in the installed state, the device does not enter the monochrome printing mode; and if even one of the three colors (CMY) is not installed, the device does not enter the color printing mode either, and an error occurs. Further, in order to switch from monochrome printing mode into color printing mode, three color (CMY) development units must be installed, and there is the problem of considerable inconvenience for the user.
Even when in color printing mode, if a monochrome print job is requested, monochrome printing is possible; but in order to put the device into a dedicated monochrome printing mode, the device must be put into a state in which only a black development unit is installed.
In the image formation device of Japanese Patent Laid-open No. 2003-316106, while installation of four color (CMYK) development units in arbitrary position is permitted in color printing mode, in order to switch into monochrome printing mode, the device must be put into a state in which only a black development unit is installed, so that once again, there is the problem of considerable inconvenience for the user.
Further, in Japanese Patent Laid-open No. 2003-43773, Japanese Patent Laid-open No. 2003-316106, Japanese Patent Application No. 2003-160059, and Japanese Patent Laid-open No. 2002-351190, there is no statement of methods for displaying to the user position information, color information, remaining amount information, or similar for installed development units. In order to enable easy switching between color printing mode and monochrome printing mode, the manner of display to the user of the position, color, and remaining toner amount for installed development units is important in order to improve convenience to the user.
Hence an object of this invention is to provide an image formation device capable of simplifying complex operations necessary for switching between color printing mode and monochrome printing mode, in order to improve convenience to the user.
A further object of this invention is to provide an image formation device which enables display of the positions, colors, and amounts of toner remaining in installed development units, to improve convenience to the user.